Patent Literature (PTL) 1 discloses a method for testing lifetime characteristics of organic electroluminescent (EL) elements used in an organic EL display device. In the testing method, the photoluminescence intensities of organic EL elements are detected at two or more different temperatures, and the lifetime characteristics of the organic EL elements are tested based on the ratio of the intensities. According to the above testing method, it is possible to test the lifetime characteristics of the organic EL elements without performing an aging test.